Portable tool for determining meat quality

ABSTRACT

A system, method and apparatus for grading of meat such as bovine, porcine, sheep, horse or poultry meat among others. The device of this invention corresponds to a portable tool, which is approached to meat specimens to be analyzed, and captures an image. The tool then objectively relates the image to meat quality parameters by means of an image analyzing method. The present invention solves in a practical, fast and satisfactory way the problem of determining meat quality parameters such as texture, color, and contained intramuscular fat percentage.

CROSS-REFERENCE TO RELATED APPLICATION

This Application claims the benefit of U.S. Provisional Application No. 60/909,222, filed Mar. 30, 2007.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 6,751,364 (incorporated herein by reference) divulges an image analysis system and method for grading of meat, predicting quality of meat and/or predicting meat yield of an animal. One embodiment of the invention is particularly designed to capture an image of the b 12 ^(th) rib cross section of the ribeye and perform an image analysis of the ribeye for grading purposes. The image capturing camera portion of the system has a wedged shaped camera housing for easy of insertion into the ribbed incision. Once the image is captured either digitally or captured and converted to a digital image, an image analysis is performed on the digital image to determine parameters such as the percentage lean, total area of the ribeye, total fat area, total lean area, percent marbling, and thickness of fat adjacent to the ribeye, and other parameters. These parameters are used to predict value determining traits of the carcass.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to a portable tool for determining meat quality with possible minimum error, thus replacing human grader with computer-assisted grader (artificial vision). Analyzed meat may be bovine, porcine, sheep or poultry meat.

The development of the present application implies developing a new method of measuring parameters such as meat fat, texture and color by means of a method, which allows relating said meat quality parameters to values obtained from images.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is the device of the present invention.

FIG. 2 is the main flow diagram of color, texture, and intramuscular analysis of a meat specimen.

FIG. 3 is a flow diagram of sub-routine capture of digital image.

FIG. 4 is a flow diagram of sub-routine that determines texture values.

FIG. 5 is a flow diagram of sub-routine, which determines intramuscular fat percentage.

FIG. 6 is a flow diagram of sub-routine that determines color (CIE-Lab coordinates).

DETAILED DESCRIPTION OF INVENTION

The present description comprises some specific technical terms, which will be detailed below in order to avoid misinterpretations regarding other uses thereof or meanings that can be connected to the same terms.

The term “artificial vision” refers to the image captured by an electronic device and the computational interpretation of said image. This term is also known as “computer vision”, and it corresponds to a sub-field of the artificial intelligence. The purpose of the artificial vision is programming a computer, which due to said programming should “understand” a scene or image features.

The term “channel” refers to a primary meat unit from an animal that was insensitized, bleeded, skinned, and gutted, where its head was cut at the atlanto-occipital joint, its external genital organs were also cut as well as its limbs, which were cut at carpometacarpal and tarso-metatarsal joints.

The term “meat texture” refers to the sensorial manifestation of foodstuff structure and the way it reacts before forces application such as shear stress. It is considered as a food-grade parameter, since it directly produces an effect on the palatability, and said effect is noted only when meat has been subjected to a boiling process. It is directly determined by properties of conjunctive myofibril structures of cytoskeleton, which differ greatly and depend on specie, race, gender, and age, thus producing an effect on technological and biological variables.

The term “intramuscular fat percentage” also referred as marbling relates to visible fat amount in a meat cut. Intramuscular fat amount produces an effect on meat flavor, tenderness and juicy character, mainly depending on gender, slaughtering age and principally on genetic type. Meat fat quality basically depends on feedstuff composition consumed by the animal during the fattening stage.

Terms such as “color space”, “color modules” or “color systems” correspond to a coordinate system and an area or sub-space within said system, where each color is represented by an single point. A color space allows specifying and visualizing any color. Psycho-physical parameters of color perception are three: brightness, tone, and saturation. In the present invention used color spaces are the following:

color space RGB, which is based on the combination of three different chromatic luminance signals: red (R), green (G), and blue (B). Graphically it is represented by a cube. Gray tones are represented by a straight line linking origin (0, 0, 0) with point (255, 255, 255) over which the three color components have the same magnitude. This corresponds to coordinated space used by electronic devices such as digital cameras and monitors.

color space “XYZ” utilizes a brightness component (component “Y”) and two coloring or chromaticity components, which corresponds to components “X” and “Z”. Components “X”, “Y”, and “Z” has a value ranging from 0 to 100. Values of each component are obtained by means of integration or adding, which involves the lighting source, object reflectance, and sensitivity curves of a standard human observer. Quantitative colorimetry utilizes three data pieces to calculate colors: the energy of the luminous source (400 to 700 nm), the reflectance of the object and the curves of sensitivity of the eye.

Color space “Lab” represents colors by means of the scale of Hunter Lab, which is one of the easiest scales to interpret in the food specialty. It uses parameters L, a, and b, where “L” measures the luminosity in a scale from 0 to 100, where 100 represent the color white and 0 represents the color black, “a” measures red tonalities (+127) until green (−128), and “b” measures yellow tonalities (+127) until blue (−128).

Lab coordinates can be obtained by means of mathematical formulae from values of coordinates XYZ and values of X₀, Y₀, Z₀, that represent the “white pattern” of the system, for example:

L*=116·(Y/Y ₀)^(1/3)−16

a*=500·[(X/X ₀)^(1/3)−(Y/Y ₀)^(1/3)]

b*=200·[(Y/Y ₀)^(1/3)−(Z/Z ₀)^(1/3)]

The term “image segmentation” refers to the technique by means of which, in an image the interest object of interest can be separated from the “background” of the image. It does tot necessarily identify the object category. For example, if it relates to a character like the letter “A”, the segmentation only identifies the image area where it is possible to find this character.

From the image a pair of referential points or pixels is selected (the corresponding minimum and maximum value in gray scale).

Each point or pixel of the image is selected according to its proximity with respect to these referential points.

Accordingly, the image points are separated in two categories, which show a similarity in their values of grays level. Particularly, these categories correspond to the group of pixels that correspond to meat and the pixels that do not correspond to meat, i.e., they correspond to the image background.

The term “thresholding” refers to a technique of image segmentation. The thresholding is the method by means of which a level of threshold “T” is chosen in order to classify each pixel of the image f (x, y) if it fulfills some property with respect to the threshold, for example f (x,y)>T, and it is assigned to the object class; otherwise, it is assigned to background class.

For example, the Otsu's method may be used as a thresholding method. This is an iterative method that calculates an optimal threshold for a standardized histogram comprising two pixel distributions. The method assumes that the histogram is formed by two Gaussian curves, and that threshold T shall minimize the weighted sum of each one of the variances of the present objects.

Tool Definition

The objective of the present invention relates to produce a portable apparatus for determining meat quality with possible minimum error, thus replacing human grader with computer-assisted grader (artificial vision). This implied the development of a new method of measuring parameters such as meat fat, texture and color by means of a method, which allows to relate said meat quality parameters to values obtained from images captured by a portable tool.

The present invention consist of a system capable of objectively measuring meat quality parameters, and for this purpose an image analyzing method is used, which allows to measure meat quality parameters with no need of manipulate the meat.

The tool of the present invention comprises a portable apparatus which is approached to meat specimens to be analyzed and it captures images; subsequently and by means of an image analyzing method it is possible to determine meat quality parameters, which shall be measured using users' understandable units. Finally, the obtained results are displayed on a screen.

The present tool (FIG. 1) consists of a casing, preferably a tubular-shaped one (a), which comprises a handle (b) on which a trigger (c) is arranged, and a screen or display (d). Inside the casing an image-capturing device is arranged (e) as well as a microcontroller (f) and they are connected to the trigger and the display respectively, in order to proceed with the actuation of the device and the data display. Furthermore, inside the casing a lighting system and as well as a light backscatter system (g) are provided with the aim of obtaining a uniform image without optical aberration. The tool of FIG. 1 further comprises a display (h) and a camera support (d).

Other components of the portable tool (not shown in FIG. 1) are electric power- and data feeder cables, which transfer the captured image to a required portable personal computer. Furthermore, a polarizing lens can be added to reduce brightness, and a filter to correct the color temperature in the opening zone (i) of the image-capturing device. (j) corresponds to the device portion, which comes in touch with the sample to be analyzed.

Some relevant aspects to be considered for the measurement of meat quality parameters are meat origin (sheep, bovine or other meat), meat type, etc. in order to determine quality parameters properly.

Image analysis is performed on a computer by an images analyzing method, which has been particularly designed for this purpose and is actuated by capturing an image, then the analysis of said image is performed and parameters results are displayed both on the screen of computer and on the display of the device of the present invention, where said parameters were measured with users' understandable units.

The indicated analysis is performed by a certain method, which allows to measure three quality parameters of meat such as meat texture, meat color, and intramuscular fat percentage, whose values are displayed in a users' comprehensible form (i.e. in measurement units used in foodstuffs science).

The process for obtaining said meat parameters begins with the approach of the involved device to a meat specimen, where said device comprises in its inner part a lighting system to homogenizing light inside said apparatus, and an images capturing device, which captures a specimen image.

The process for obtaining meat quality parameters from an image is semi-automatic controlled by a computational programming, which is run by the operator once the specimen images capturing-device is triggered. Said programming controls orders of the images capturing device and subsequently it processes the captured image in order to display it then on a screen. Once the computational programming is run, it checks the apparatus status, which includes verification of the status of the images-capturing device, among others. Verification of the status of the images-capturing device checks feeding status, memory status, communication with the computer, etc. If there is any erroneous parameter the programming shows an error message; if not, said programming goes through an automatic configuration process of the device intended for images-capturing process. The configuration states image format, image storage location—which can be either a temporal location or a location for storing the corresponding image for future verifications, exposure time, focus adjust, diaphragm opening, white balance, etc. Once ready, image is captures and it is stored in the previously selected address. Subsequently the programming checks the images-capturing device once more.

In the present invention the artificial vision is used for determining meat quality parameters.

In order to perform the images analysis a technique about Artificial Neural Networks (RNA due to it Spanish abbreviation by initials) is utilized. Artificial Neural Networks such as backpropagation are capable of “learning” and due to this feature said artificial neural networks can transform data captured from image into data of any other nature (conventional methods) such as data obtained by a Warner—Bratzler calorimeter, etc. Artificial Neural Networks (RNA) are prepared such that they can connect an inlet value to an outlet one. In the present invention said inlet value corresponds to a value obtained from data selected from the captured specimen image, whereas said outlet value refers to the result of the respective parameter, which is obtained by a physical or chemical method regarding the same specimen.

Outlet values for each parameter are intramuscular fat percentage, meat texture and color, which are determined by means of the following physical techniques.

Determination of Intramuscular Fat

The method of determining intramuscular fat percentage is based on the technique relating to the use of a graduated jig according to National Cattlemen's Beef Association; United States Department of Agriculture.

In said method a tag-blog is provided on the wet specimen, which shows a squared grid drawn thereon. Then the operator proceeds to count those zones corresponding either to meat or fat inside said squared grid. Intramuscular fat percentage is calculated by means of a simple three rule.

Texture Determination

The method for determining meat texture is based on Warner-Bratzler's technique.

From each meat cut cores cylinders also referred as “cores” having a diameter of about 1.27 cm and a height of about 2.5 cm are obtained, wherein each cylinder shall be oriented parallel to muscle fibers. Then temperature is adjusted to 1-3° C., and subsequently said specimens are subjected to room temperature. After 5 minutes each cylinder (core) is sheared by means of a Warner-Bratzler probe executing a cut perpendicular to muscle fibers once at a rate of 200 mm/min and an approach rate of 80 mm/min and a pre-load of 0.01 Kg.F.

A texturometer having a maximum load cell of 500N (DO-FB05TS Model 2003, Zwick, Ulm, Germany) was utilized. Texture is expressed as Maximum Force at Kg.F with a mean value of 6 measurements.

Color Determination

Method for determining meat cut was carried out by measuring specimen reflectance. Said reflectance analysis was performed on a Miniscan XE Plus model N° 45/0-1 Hunterlab, which utilizes CIELAB system expressing results in terms of variables L, a and b. Six measurements of each specimen are performed and these are made on specimen surface. Equipment is programmed at an observation angle of 10° with illuminant D65, which is similar to daylight, using an absolute scale for coordinates L, a and b, wherein color is defined in a three-dimensional and spherical space. Mean value of the 6 measurements represent the value of each variable.

Image analyzing method comprises the following stages: color analysis, texture analysis and analysis of meat fat percentage, and then obtained results are finally displayed on screen in a users' understandable manner.

Meat Texture Analysis

Texture analysis is performed by means of an analysis sub-routine, which begin with the recovery of image stored in a defined address in the computer hard disc. To this image clustering function is applied, which cut or segments image to be analyzed, selecting from said image only areas representing a meat image, and the remaining elements are discarded (image background). Then the image is subdivided in several sub-images of less size, e.g., of 128×128 pixels. Each of these images is analyzed to determine whether they correspond to meat or background (background is black; if image contains black pixels it will be discarded). Finally considered images are subjected to a Wavelet analysis by which a vector comprised of 8 RMS values for each sub-image or sub-area is obtained. Once this data is obtained and by means of a co-relation made by the prepared Artificial Neural Network, obtained variables are converted to a single shearing-force value. Obtained values for each images are averaged at a final stage, and said mean value, which is referred as F_(TOTAL), is the value corresponding to the mean texture measurement.

Analysis of Intramuscular Fat Percentage

Another relevant parameter is the mean quality measurement, which corresponds to the intramuscular fat percentage contained in a meat cut.

The process for obtaining the value of intramuscular fat percentage begins with the recovery of image stored in computer hard disc. Then the program accentuates interest zones of said image by means of simple linear and non-linear operations such as multiplying the image by itself, filtering undesired brightness, adjusting intensity, etc. In this manner a superior contrast between image and background is reached and in this point image segmentation is performed in order to separate background from interest zone.

Image coordinates RGB are converted into coordinates CMY (better resolution) and then the colored image is converted into a gray-scale image. Subsequently a thresholding method is applied, which uses an adaptive method to look for the proper threshold according to histogram of image being analyzed in order to achieve a discrimination among different grays tones that correspond to white and black.

Then a counting of white and black pixels is carried out, thus obtaining fat and meat areas in the cut. Subsequently areas corresponding to fat and meat are calculated and they are converted into intramuscular fat percentage contained in the cut. This result is finally displayed on a screen.

Color Analysis of Meat Specimen

The color obtaining process begins with the recovery of image stored in computer hard disc. Subsequently the number of pixels of this image is reduced and then the image portion to be analyzed is segmented by means of a function referred as clustering, considering meat zones only. From this image coordinates RGB are obtained, which are specimen representative. Then the artificial neural network converts RGB color space into XYZ color space of colored zones (meat zones) and differentiates colored zones through data co-relation to convert previous coordinates into XYZ coordinates, and then into CIE Lab coordinates. Finally CIE Lab coordinates are displayed and recorded, thus obtaining mean color of analyzed meat cut and the program is ready to start again. 

1. Process for grading of meat such as bovine, porcine, sheep, poultry meat or others with no need of manipulate meat specimens by means of a portable tool comprising an image-capturing device and an image analyzing method, CHARACTERIZED in that values of meat quality parameters such as meat texture, intramuscular fat, and color are obtained due to management of data from a digitalized image of a meat specimen by a neural network system.
 2. The process for grading of meat according to claim 1, CHARACTERIZED in that said neural networks system corresponds to a backpropagation type or they can learn to convert data captured from the image into data of other nature.
 3. The process for grading of meat according to claim 1, CHARACTERIZED in that the texture parameter of meat specimen is obtained following the next stages: capturing an image; segmenting said image (clustering function), where said segmentation stage only selects areas representing a meat image, and discards the remaining elements; dividing said image into several sub-images having the same size; calculating wavelet for each sub-image, from which a vector of RMS values is obtained for each sub-image; co-relating in the RNA backpropagation, which relates each vector to a shear force value; calculating the mean value of values obtained from shear forces of each sub-image.
 4. The process for grading of meat according to claim 1, CHARACTERIZED in that the parameter of intramuscular fat percentage of meat specimen is obtained following the next stages: capturing an image; accentuating interest zones of said image by filtering brightness, intensity adjust, etc. segmenting said image (clustering function), where said segmentation stage only selects areas representing a meat image; converting image RGB coordinates into CMY coordinates; converting the image into a gray-scale image (mean calculation in each pixel of color coordinates); classifying in white and black by means of adaptive thresholding of image; counting white and black pixels; calculating percentage of fat area (white area percentage) and meat (black area percentage).
 5. The process for grading of meat according to claim 1, CHARACTERIZED in that the color parameter of meat specimen is obtained following the next stages: capturing an image; reducing the number of pixels of said image; segmenting said image, where said segmentation stage only selects areas representing a meat image; obtaining representative RGB coordinates; converting RGB coordinates into the color space XYZ; converting XYZ coordinates into coordinates CIE Lab; associating color values in CIE Lab coordinates by means of RNA backpropagation with a colorimetry value; displaying on screen the obtained results.
 6. A tool for determining meat quality parameters with no need of manipulate meat comprising an image capturing device and an image analyzing method, CHARACTERIZED in that said tool comprises a structure or casing with a handle, and inside the casing an image-capturing device is arranged as well as a lighting system and a light backscatter system connected to a microcontroller, which is connected to a screen, on which the obtained results are displayed, and to a actuation trigger.
 7. The tool according to claim 6, CHARACTERIZED in that the image capturing device can capture an image with a resolution of at least 400×600 pixels.
 8. A method for determining meat quality in an objective manner, without manipulating meat, CHARACTERIZED in that said method comprises the use of a portable tool, which is approached to a meat specimen in order to capture an image, where said image is then analyzed by an objective method of image analysis, and subsequently the variables determining the quality of the analyzed meat specimen are displayed on the tool screen. 